(CNN) -- Broken bodies of children. A dead mother. A wailing father.
That was the scene outside of a school in the northern Iraqi city of Mosul, where authorities said more than 100 people were killed Friday in fighting between security forces and al Qaeda-backed Sunni fighters.
The fighting follows news a day earlier that militants tried to take control of the city of Samarra to the south, violence spurred in part by an escalating conflict between Iraq's majority Shiite government and a Sunni minority who claim they are disenfranchised.
The violence has left hundreds dead in recent months, raising fears it could return Iraq to the level of violence in 2006 and 2007, when bodies littered the streets.
Nearly 500,000 people are estimated to have been displaced this year in fighting, primarily in the Sunni-dominated Anbar province, the United Nations refugee agency said Friday.
But that number is expected to climb, said Adrian Edwards, the spokesman for the U.N. High Commissioner on Refugees.
On Friday, Hares Hammadi al-Bajari was among dozens trying to flee the fighting in Mosul, where militants were attacking police stations and security checkpoints.
With a round-the-clock curfew in effect that banned people from driving, Bajari, a taxi driver, set out on foot with his family to try to make it to safety in the nearby Kurdish-controlled Duhok province.
"Kurdish security forces were welcoming families," police Lt. Salah Othman said.
But as Bajari neared the checkpoint on the outskirts of Mosul's al-Zahraa neighborhood, according to Othman, fighting resumed.
The family was forced to regroup outside a school to wait for a lull in the fighting and try again, he said.
That's when a barrage of mortars struck near the building, landing among the families.
A video posted on Facebook purports to show the aftermath of the bombing.
A man can be heard screaming: "Let them see. ... See these children? See what's left from the mortar round? They are targeting women, and these dead children."
The footage shows the bodies of a number of children, including some missing body parts.
CNN cannot confirm the authenticity of the video. But it correlates with the description of the attack given to CNN by Othman.
At least 17 people were killed in that attack, according to Iraqi health officials.
Another 55 people, including 22 Iraqi police and 33 militants, were killed and 43 wounded in fighting that broke out across the city, the health officials said.
Scores more were killed when gunmen and several suicide bombers attacked an Iraqi munitions storage in western Mosul, security forces said.
By nightfall, Iraqi security forces had retaken control of a number of the police stations and checkpoints, authorities said.
The fighting in Mosul mirrored an attack a day earlier in Samarra, when gunmen attacked security checkpoints and took control of portions of the city.
The attackers are believed to be members of the Islamic State in Iraq and Syria, an al Qaeda splinter group also known by its acronym ISIS.